Japanese Patent Application Publication Number H11-329637 issued Nov. 30, 1999 discloses connection apparatus between printed circuit boards, which is formed of a transmission connector and a reception connector. The transmission connector is a molded interconnect device (MID) including a light emitting element, and is mounted on a first printed circuit board. The reception connector is an MID that includes a light receiving element facing the light emitting element, and is mounted on a second printed circuit board piled on the first printed circuit board. Since this apparatus transmits an optical signal through the light emitting element and light receiving element, contacts to be connected each other can be omitted. However, the apparatus is configured to be located between two printed circuit boards, and accordingly cannot be used for optical communication with external devices. In addition, print circuit boards cannot be placed side by side in a horizontal direction.
Japanese Patent Application Publication Number H11-214100 issued Aug. 6, 1999 discloses hybrid optical-electrical connector apparatus that is formed of a hybrid plug and a hybrid socket. The plug is formed of an upper and lower cases, and has an optical signal transmitter, an optical signal receiver and a power plug. The transmitter and receiver are connected to two optical fiber cables included in a hybrid cord, respectively. The power plug is connected to a power cord included in the hybrid cord. The socket is formed of case and cover that contain a print circuit board mounted with a light emitter, a light receiver, a power jack and an external connector. The light emitter is mounted on the front of the board to face the optical signal receiver of the plug connected to the socket. The light receiver is mounted on the front of the board to face the optical signal transmitter of the plug connected to the socket. The jack is mounted on the front of the board to be electrically connected with the power plug of the plug connected to the socket. The external connector is mounted on the back of the board to be electrically connected with a connecter from external. If plug-socket connector apparatus is formed based on this apparatus of plug-socket-socket coupling type, namely the external connector is omitted, optical communication with external devices becomes possible through the optical fiber cables (hybrid cord). In addition, print circuit boards can be placed side by side in a horizontal direction.
However, since the hybrid plug is connected to the hybrid socket in a vertical posture with respect to the print circuit board, thickness dimension of an electronic product equipped with the plug-socket connector apparatus becomes large. In addition, the hybrid plug is formed of the upper and lower cases, and accordingly the thickness dimension is further increased. Moreover, since the square shaped optical signal transmitter and optical signal receiver are plugged in two square shaped cavities of the hybrid socket, respectively, stress is put on the optical signal transmitter and optical signal receiver as well as the two cavities through the hybrid cord (optical fiber cables).
FIGS. 19A and 19B show a photoelectric conversion connector which has been proposed conventionally. This connector comprises a plug 900 connected with an optical fiber cable, an MID substrate 920 detachably connected with this plug 900, and a metal shell 930 to which the plug 900 and MID substrate 920 are attached. The plug 900 has a plug body 901 formed of a rectangular synthetic resin mold. The left and right sides of the facing surface (the front face) with the MID substrate 920 in the plug 900 are formed with a pair of fit projections 902 projecting to the MID substrate 920 side. The front faces of the fit projections 902 are formed with openings of one side of a through hole 903 piercing the plug body 901 in the front and back direction, respectively. Two optical fiber cables 910 are inserted into the through holes 903 from the back side and then and fixed. The facing surface with the plug 900 in the MID substrate 920 is formed with a pair of fit cavities 921 into which the pair of fit projections 902 are fit, respectively. An optical element (a light emitting element or a light receiving element) 922 is mounted on the facing part with the end face of the optical fiber cable held by the plug 900 in the bottom of each fit cavity 921. The metal shell 930 comprises a rectangular bottom plate part 931, three hold spring parts 932 and three hold spring parts 933. The plug 900 and MID substrate 920 are put on the bottom plate part 931. The three hold spring parts 932 project from the front edge and the front side of left and right edges in the bottom plate part 931 toward upside, respectively and hold the MID substrate 920. The three hold spring parts 933 project from the back edge and the back side of left and right edges in the bottom plate part 931 toward upside, respectively and hold the plug body 901.
When the plug 900 is connected to the MID substrate 920, the MID substrate 920 is inserted into the metal shell 930 from upside. Each hold spring part 932 is then latched to the MID substrate 920. Consequently, the MID substrate 920 is fixed to the metal shell 930, and a receptacle is obtained. The plug 900 is then inserted into the receptacle from upside. In the state that the fit projections 902 of the plug body 901 are fit into the fit cavities 921 of the MID substrate 920, each hold spring part 933 is latched to the plug body 901. Thereby, the plug 900 is connected to the receptacle, and the optical fiber cables 910 of the plug 900 face the optical elements 922 mounted on the MID substrate 920.
In this photoelectric conversion connector, the plug 900 is connected to the metal shell 930 fixing the MID substrate 920 form the vertical direction of the optical axes of the optical elements 922 mounted on the MID substrate 920. Because of this, there is an issue that positioning precision between the optical axes of the optical fiber cables 910 held by the plug 900 and the optical axes of the optical elements 922 is low, and also the position relationship of the optical axes changes when the optical fiber cables 910 held by the plug 900 receive stress, so that transmission loss increases. Also, the optical elements 922 are mounted on the facing surface with the plug 900 in the MID substrate 920, but there is another issue that influence of noise and so on increases in case that electrical separation between the optical elements is insufficient. In addition, as shown in FIG. 19B, in the state that the plug 900 is connected to the receptacle, the upside of attachment and detachment direction of the plug 900 in the connector is not shielded, and accordingly shield performance cannot be secured.